The first section of a new “floating” bridge that will be installed at Harlech Castle arrived at the medieval monument today.

Work to install the spectacular structure, which will allow visitors to enter the site through the original historic entrance for the first time in over 600 years, is expected to start at around 9am tomorrow morning when two sections of the bridge will be lowered into place by a gigantic 200-tonne crane.

But the work experienced an unexpected setback earlier today when a lorry carrying the 70-tonne base of the crane drove too far down a hill near the site entrance.

The truck’s massive load was too heavy to reverse back up toward the drop-off point near the site, leaving the vehicle stuck blocking a narrow road in the Glan-y-Wern area of the town.

It meant that the bridge itself, which was being carried on the back of a lorry, was left stranded at a lay-by between Harlech and Talsarnau for a period earlier whilst the situation was resolved.

A Cadw spokesman said: “There was a panic for a little bit. Everything has been sorted out now.

“The issue was with a lorry and we have recovery on site. The first section is on site and the second and third sections will be ready tomorrow.”

“We’re all on schedule.”

Once completed, the walkway will create a link from the terrace area directly into the castle’s gatehouse at the World Heritage Site.

The steel-constructed bridge was built in three sections by S H Structures in York and painted white in Widnes.

As well as the installation of the bridge, the town’s former Harlech Castle hotel and car park will also be revamped as the £5.8m project.

The ground floor of the disused hotel will become a brand new visitor centre complete with state of the art audio-visual displays, a shop and a tearoom.

The first and second floors of the hotel will also be refurbished into five 5-star apartments for visitors.

As part of the scheme, project bosses Cadw has received permission from the Countryside Council for Wales to relocate bats that were roosting in the gatehouse.

They have devised a scheme with ecologists to construct a new bat roost which has been installed in the castle’s north-east tower.

The work has been funded through the Heritage Tourism Project which works in partnership with various heritage bodies to deliver improvements to historic monuments and sites.

In local mythology, the site of Harlech Castle is associated with the legend of Branwen, a Welsh princess.

It was built by Edward I during his invasion of Wales between 1282 and 1289 at the substantial cost of £8,190.

It withstood the siege of Madog ap Llywelyn between 1294–95, but fell to Owain Glyndŵr in 1404.

It then became Glyndŵr’s residence and military headquarters for the remainder of the uprising until being recaptured by English forces in 1409. During the 15th century Wars of the Roses, Harlech was held by the Lancastrians for seven years, before Yorkist troops forced its surrender in 1468, a siege memorialised in the song Men of Harlech.

Following the outbreak of the English Civil War in 1642, the castle was held by forces loyal to Charles I, holding out until 1647 when it became the last fortification to surrender to the Parliamentary armies.

It is considered by UNESCO to be one of “the finest examples of late 13th century and early 14th century military architecture in Europe”.